The present invention relates to a process cartridge, an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, and a process cartridge mounting method.
Here, the electrophotographic image forming apparatus (image forming apparatus) is an apparatus which forms an image on a recording material using an electrophotographic image forming process, and examples of the apparatus include an electrophotographic copying machine, an electrophotographic printer. (an LED printer, a laser beam printer or the like), an electrophotographic printer type facsimile machine, an electrophotographic printer type word processor and the like.
The process cartridge is a cartridge containing as a unit an electrophotographic photosensitive member and a charging means, developing means or cleaning means, which cartridge is detachably mountable as a unit to the main assembly of the image forming apparatus. Another example of the process cartridge includes as a unit an electrophotographic photosensitive member and at least one of charging means, developing means and cleaning means, wherein the process cartridge is detachably mountable as a unit to the main assembly of the image forming apparatus. A further example of the process cartridge includes an electrophotographic photosensitive drum and at least developing means, and is detachably mountable as a unit to the main assembly of image forming apparatus.
A yet further example of a process cartridge includes a cleaning unit containing as a unit charging means, cleaning means and a photosensitive drum, and a developing unit constituted as a unit developing means and toner to be supplied to developing means. In this case, the cleaning unit and the developing unit are coupled with each other by a coupling member into a process cartridge.
Heretofore, in image forming apparatus forming an image on a recording material using an electrophotographic image forming process, a cartridge system has been used in which the electrophotographic photosensitive member and process means actable on the electrophotographic photosensitive member are constituted into a unit (cartridge) which is detachably mountable to image forming apparatus. With the use of the process cartridge type, the maintenance operation can be carried out in effect by the users without the necessity of relying on serviceman, and therefore, the operability is improved. For this reason, it is widely used in the image forming apparatus.
However, the size of the process cartridge increases with the increase of the capacity which has been necessitated due to the demand for higher speed and the longer service life. Further improvement in the operability is desired.
The heavier process cartridge requires a correct positioning system durable against the weight.
Accordingly, it is a principal object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus in which the operability in the mounting and demounting of a process cartridge relative to the main assembly of the apparatus is improved. It is another object of the present invention to provide a process cartridge, a process cartridge mounting method and an electrophotographic image forming apparatus in which the process cartridge can be positioned in the main assembly of apparatus with high accuracy.
It is a further object of the present invention to provide a process cartridge, a process cartridge mounting method and an electrophotographic image forming apparatus in which the process cartridge is lowered to a predetermined position in the main assembly of the apparatus.
It is a further object of the present invention to provide a process cartridge, a process cartridge mounting method and an electrophotographic image forming apparatus in which the operability in the mounting of the process cartridge is improved.
It is a further object of the present invention to provide a process cartridge, an electrophotographic image forming apparatus and a process cartridge mounting method in which the operability is good, and the positioning accuracy is improved.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.